Within two decades the number of victims will have risen to a million, with the bill soaring by many more billions. Yet the NHS's rationing watchdog NICE has banned Alzheimer's drugs which could hugely reduce that bill - even though they cost just £2.50 per patient per day.

That is why we are inviting our readers to join our For The Sake of £2.50 campaign, backing the Alzheimer's Society, which is mounting a legal challenge to the NICE decision in the High Court.

It needs to raise many thousands to pay for the action, expected to start next month, which it is hoped will prove the process leading to the restrictions was unfair. The drug companies Eisai and Pfizer are leading a separate legal action on the restrictions - and are not contributing to the Alzheimer's Society campaign.

Britons with dementia already have less access to diagnostic services and treatment options than patients in other EU countries. But today a report titled Dementia UK, commissioned by the Alzheimer's Society, shows that the Government has no plans for dealing with the explosion in sufferers.

Instead the problem could grow worse as prescription drugs are withheld from patients from whom they might make a difference - until their symptoms deteriorate.

Three drugs, Aricept, Exelon and Reminyl, are no longer available for patients with 'mild' Alzheimer's in England and Wales although they are licensed in Scotland.

They compensate for low levels of a chemical within the brain which helps nerve cells to communicate, temporarily improving or stabilising symptoms in about half of patients who try them.

Only patients with 'moderate' symptoms are eligible for these medicines, while a new drug called Ebixa which improves severe behavioural problems can be used only as part of a clinical trial.

Thousands of patients and carers, doctors and specialists in care of the elderly have protested over the decision by NICE, the National Institute for Health and Clinical Excellence. Neil Hunt, chief executive of the Alzheimer's

Society, said the Government was sending out the wrong message to patients and their families. Spending a little money now on drugs which can slow the disease makes good economic sense in the medium and long term, he said.

"The Dementia UK report clearly shows that to reduce the burden of dementia on individuals and society we need to try to delay the progression of the disease.

"This will not only save money but most importantly improve people's quality of life. That is why NICE decision to restrict the use of Alzheimer's drugs on the NHS makes no sense.

"NICE has got its sums wrong. It hasn't taken into account the true cost of dementia care, to the NHS, social services, families and individuals.

"For too long the true cost of dementia has been hidden. Today we can say for sure: This

is what dementia costs, let's now put proper plans in place."

The Dementia UK report was prepared by the London School of Economics and King's College, London. It says the cost of £17billion each year includes NHS and social services, lost income and taxes from carers, and the estimated contribution from unpaid carers.

Delaying the onset of dementia by five years would halve the number of related deaths, saving nearly 30,000 lives annually.

Mr Hunt said: "The NICE decision ignores the benefits these treatments offer legions of unpaid carers and the millions of pounds they save the country every year. Drug treatments are just one part of the care and treatment that a person with dementia needs but they can be a very vital part."

Actor Richard Briers starred as a husband caring for his wife with Alzheimer's in the 2005 BBC film Dad. He said at the time he was greatly affected by the research he did for the role.

He said: "Thank you to the Daily Mail for backing the campaign to overturn this disastrous decision by NICE. "2.50 is such a small price to pay for treatment which can make a world of difference to the thousands with Alzheimer's and the millions more who care for a loved one with this devastating disease."

Health Minister Ivan Lewis insisted that the Government took the issue of dementia very seriously.

"We have made a strong commitment to improving services for people with Alzheimer's disease and other forms of dementia. Alzheimer's disease is one of four areas targeted to benefit from an extra £100million per year research and development funding by 2008."